This paper studies how word-of-mouth communication aggregates information among individual agents, showing that the structure of communication determines whether all agents end up making identical choices. The study finds that less communication increases the likelihood of conformity. Despite players' naive decision rules and a stochastic environment, word-of-mouth communication may lead all players to adopt the action that is on average superior. These socially efficient outcomes occur when each agent samples only a few others. The paper examines two environments: one where two competing products have unequal qualities, and another where two equally good products are considered. It shows that the structure of communication affects whether the population learns to use the superior product or exhibits diversity in choices. The study uses a simple nonstrategic environment with a large population of identical players, each choosing between two actions. Payoffs are influenced by stochastic shocks, and players rely on word-of-mouth communication to gather information. The paper introduces two key assumptions: (1) players do not search for information optimally but instead hear about the experiences of a random sample of N other players, and (2) players exhibit inertia, often continuing with their previous choice. The study finds that word-of-mouth communication can lead to efficient social learning, where all players eventually adopt the superior action, even when the communication is limited. This occurs when each individual receives very little information. The paper also explores the implications of different communication structures, showing that larger sample sizes can lead to diversity, while smaller samples increase the likelihood of conformity. The study highlights the role of "must-see" restrictions, where players only consider switching if they hear about the choice they are currently using. This restriction incorporates a form of popularity weighting, allowing less popular technologies to die out. The paper concludes that the structure of word-of-mouth communication significantly affects the tendency of a population to display conformity or diversity. When communication is limited, conformity is more likely, but when communication is extensive, diversity is more likely. The study also shows that efficient social learning can occur even with limited communication, as the superior action is adopted by all players over time. The results have implications for understanding how information spreads and how decisions are made in social learning contexts.This paper studies how word-of-mouth communication aggregates information among individual agents, showing that the structure of communication determines whether all agents end up making identical choices. The study finds that less communication increases the likelihood of conformity. Despite players' naive decision rules and a stochastic environment, word-of-mouth communication may lead all players to adopt the action that is on average superior. These socially efficient outcomes occur when each agent samples only a few others. The paper examines two environments: one where two competing products have unequal qualities, and another where two equally good products are considered. It shows that the structure of communication affects whether the population learns to use the superior product or exhibits diversity in choices. The study uses a simple nonstrategic environment with a large population of identical players, each choosing between two actions. Payoffs are influenced by stochastic shocks, and players rely on word-of-mouth communication to gather information. The paper introduces two key assumptions: (1) players do not search for information optimally but instead hear about the experiences of a random sample of N other players, and (2) players exhibit inertia, often continuing with their previous choice. The study finds that word-of-mouth communication can lead to efficient social learning, where all players eventually adopt the superior action, even when the communication is limited. This occurs when each individual receives very little information. The paper also explores the implications of different communication structures, showing that larger sample sizes can lead to diversity, while smaller samples increase the likelihood of conformity. The study highlights the role of "must-see" restrictions, where players only consider switching if they hear about the choice they are currently using. This restriction incorporates a form of popularity weighting, allowing less popular technologies to die out. The paper concludes that the structure of word-of-mouth communication significantly affects the tendency of a population to display conformity or diversity. When communication is limited, conformity is more likely, but when communication is extensive, diversity is more likely. The study also shows that efficient social learning can occur even with limited communication, as the superior action is adopted by all players over time. The results have implications for understanding how information spreads and how decisions are made in social learning contexts.